Local Backup/Restore should lock app

[Rojikku]

Steps to reproduce

Local Backup/Restore

Expected behavior

Backup:

• Some progress notification or something
• Asks for file name before completion
• Just save it to that file name when you're done
• Notification for completed backup like GDrive has

Restore:

• Full screen popup/lockout
• Progress bar with some animation so I know it's not frozen
• Ideally able to switch out of app while it works
• Completion screen/notification
• Just do a soft app restart after I hit OK when it's done or something, so stuff displays

Actual behavior

Backup:

• App maybe gives a toast
• No indication of progress
• Multiple saves all at once when it does work
• Interrupted backups can save with incomplete data which may trick users into believing they can cancel the others with no consequence, while the first failed
• Yes other people will definitely do this

Restore:

• My backup was 20MB
• Toast pops up, then nothing for like 10 minutes. Maybe it failed. Maybe I missed it.
• Try again, toast pops up, like 5 minutes later I see a ton more toasts.
• App is not remotely restored, but I do see chapter data
  • Obvious UI/DB desync
• Restart app, all is good

LNReader version

2.0.0

Android version

Android 16

Device

PIxel 8 Pro

Other details

No response

Acknowledgements

• [x] I have searched the existing issues and this is a new ticket, NOT a duplicate or related to another open or closed issue.
• [x] I have written a short but informative title.
• [x] If this is an issue with a source, I should be opening an issue in the sources repository.
• [x] I have updated the app to version 2.0.0.
• [x] I will fill out all of the requested information in this form.